Efficacy The primary efficacy variable of intermittent dose of IM (INTERIM) is measured by the proportion of patients who maintain a stable CCgR over the whole study period (12 months). For the purposes of this study the monitoring of the cytogenetic response (CgR) status will be evaluated by Fluorescence-in-situ-Hybridization (FISH) of interphase peripheral blood cells (molecular cytogenetic analysis)